Conventional filter connectors of this type, for example, filter connectors for automobile applications to reject high frequency noise are constructed as shown in FIG. 8. The filter connector 1 comprises an insulation housing 2, an electrically-conductive shield case 3 covering the insulation housing 2, cylindrical capacitors 4 extending through the shield case 3 and soldered thereto, and electrically-conductive post or tab contacts 5 extending through the housing 2 and the capacitors 4 and soldered thereto. One end of each contact 5 is bent. The housing 2, the shield case 3 and the capacitors 4 are made of plastic, electrically-conductive metal and ceramic dielectric material, respectively. Also, the capacitors 4 include metal film electrodes.
The filter connector 1 is mounted on a printed circuit board 6 in such a manner that the contacts are inserted into through holes formed in circuit patterns on the circuit board 6. The filter connector 1 is mated with a complementary connector.
However, as understood from the above description, the contacts 5 of the conventional filter connector 1 are connected to the capacitors 4 in the metal shield case 3 and in engagement with the plastic housing 2. It is known that the materials of the housing 2 and the shield case 3 differ in thermal expansion coefficient. Additionally, one side surface of the housing 2 to retain contacts 5 is continuous. If the filter connector 1 having such housing 2 and shield case 3 is used under a certain environment encountering wide temperature changes, such difference in thermal expansion coefficient will cause displacement between both fixed points and, in turn, stress which will bend the contacts 5. A part of the stress affects the capacitors 4, thereby causing cracks in them which reduces capacitance or damaging the capacitors 4.
Also, when the housing 2 is mated with or unmated from a matable complementary connector to insert or extract contact sections of the contacts 5 with respect to contact sections of the complementary connector, bending force known as "kojiri" is caused at the contact sections and transmitted to the capacitors, thereby causing the aforementioned damage to the capacitors.
One conventional means to avoid such problems is to reduce the number of contacts in a filter connector which decreases the entire physical dimension of such connector, thereby limiting the total magnitude of stress due to different coefficients of thermal expansion within a tolerable range. This requires a plurality of housings each having a relatively small number of contacts if one needs a filter connector having a large number of contacts. Such housings are accommodated in a common shield case. However, such a filter connector suffers from reduced contact installation, density, limits freedom of contact arrangement, and makes connector assembly more complicated and expensive.
It is, therefore, an object of this invention to overcome the aforementioned problems and to provide a filter connector free from stress due to different coefficients of thermal expansion even if it is used under wider temperature changing conditions.
It is still another object of the present invention to provide a filter connector capable of avoiding such troubles in capacitors due to "kojiri".